DRM workaround: Kindle for Android

[DuckieTigger]

Originally Posted by ottischwenk

Did you find a solution to get a "working" backup.ab?

I don't believe he did find a solution with backup. But he did find a solution to get the key out. No need for backup if you can get the smaller databse file out to let the plugin extract the key from there. See this post: https://www.mobileread.com/forums/sh...&postcount=124

[ownedbycats]

Added this to OP, though perhaps the wording isn't the best:

Note that there are reports that the apk won't work for Android 11, and that at least on Android 10 the app may attempt to force the user to upgrade to download books. 32-bit Nougat on Bluestacks is confirmed to work.

[jhowell]

I have been experimenting with Kindle for Android under BlueStacks with Nougat 64-bit and have seen some odd behavior. I used Kindle for Android versions 4.16.0.75 and 8.51.1.0.

The 8.51 version was released late last year and is the newest version that is supported on older Android devices. I own a Nexus 7 tablet running Android M and that is the most recent version available from the Google Play Store for that device. Newer Android devices are currently at version 8.73.

Kindle for Android 8.51 on my Nexus 7 downloads most books in KFX format. However the same APK installed under BlueStacks N64 downloads the same books in KF8 format with a .prc extension instead. There are tricks that can be used to force Kindle for PC/Mac download KF8 instead of KFX. It seems that running under BlueStacks has the same effect on Kindle for Android!

There is a significant difference between K4A 4.16 and 8.51 in the book files downloaded. Version 4.16 downloads KF8 files with standard definition images, equivalent to what you get using Download & Transfer from amazon.com. However version 8.51 downloads an additional AZW6 file for many books with higher quality images.

Higher resolution images from Kindle for PC can be processed when adding to calibre using the AZW6 Image Merge plugin. And I previously created an update to that plugin to handle files from e-ink Kindles. I may produce another update to also handle high definition images from Kindle for Android if there is any interest.

[ottischwenk]

Originally Posted by DuckieTigger

I don't believe he did find a solution with backup. But he did find a solution to get the key out. No need for backup if you can get the smaller databse file out to let the plugin extract the key from there. See this post: https://www.mobileread.com/forums/sh...&postcount=124

Please excuse the misleading post with the 47 bytes.
I get this 47 bytes backup.ab from a Likebook Ares (Android 8.1) on which the Kindle app mentioned at the beginning has been installed.
And because as a Notes device I almost always have it with me, I would prefer it to the Bluestacks solution, which btw works for me.

And that's why I'm looking for a solution to get the app key.

Edit: I found a solution. I uninstalled and reinstalled with an old Total Command App.

[patrik]

I've used the 4.16 app on an old mobile (android 8) and it has worked great, until now. Today I got the message "Item not available for this device type. An app update is required to read this title. Please visit.. etc.".

Even though I'm a Kobo user I have bought almost all my ebooks on Amazon (out of pure habit I suppose). That has now changed.

[ottischwenk]

Originally Posted by patrik

I've used the 4.16 app on an old mobile (android 8) and it has worked great, until now. Today I got the message "Item not available for this device type. An app update is required to read this title. Please visit.. etc.".

When, where and why did you get this message.
What were you trying to get?

[ownedbycats]

Still working for me.

Are you receiving it for all books? If not, if not too personal which book(s) did you try to download?

[patrik]

It was for several books (I checked a few, all newer than Jan 3).

Here is a free book you can check if you like:

https://www.amazon.com/Know-What-You...dp/B0BX4B1VX5/

[patrik]

Originally Posted by ottischwenk

When, where and why did you get this message.
What were you trying to get?

When pressing on a new book in the app, normally it will start to download, and then a checkmark appears on the book cover. But now a "!" appears instead, and a window pops up with the text I mentioned.

[j.p.s]

Originally Posted by jhowell

Higher resolution images from Kindle for PC can be processed when adding to calibre using the AZW6 Image Merge plugin. And I previously created an update to that plugin to handle files from e-ink Kindles. I may produce another update to also handle high definition images from Kindle for Android if there is any interest.

If you do more work on this plugin, would you also consider enabling it to run using calibre-debug -r ?

[ottischwenk]

Originally Posted by patrik

It was for several books (I checked a few, all newer than Jan 3).

https://www.amazon.com/Know-What-You...dp/B0BX4B1VX5/

I had no problems downloading to my Likebook P78.

[DuckieTigger]

Originally Posted by jhowell

I have been experimenting with Kindle for Android under BlueStacks with Nougat 64-bit and have seen some odd behavior. I used Kindle for Android versions 4.16.0.75 and 8.51.1.0.

The 8.51 version was released late last year and is the newest version that is supported on older Android devices. I own a Nexus 7 tablet running Android M and that is the most recent version available from the Google Play Store for that device. Newer Android devices are currently at version 8.73.

Kindle for Android 8.51 on my Nexus 7 downloads most books in KFX format. However the same APK installed under BlueStacks N64 downloads the same books in KF8 format with a .prc extension instead. There are tricks that can be used to force Kindle for PC/Mac download KF8 instead of KFX. It seems that running under BlueStacks has the same effect on Kindle for Android!

There is a significant difference between K4A 4.16 and 8.51 in the book files downloaded. Version 4.16 downloads KF8 files with standard definition images, equivalent to what you get using Download & Transfer from amazon.com. However version 8.51 downloads an additional AZW6 file for many books with higher quality images.

Higher resolution images from Kindle for PC can be processed when adding to calibre using the AZW6 Image Merge plugin. And I previously created an update to that plugin to handle files from e-ink Kindles. I may produce another update to also handle high definition images from Kindle for Android if there is any interest.

I would be very interested in adding functionality to the AZW6 Image Merge plugin to allow the AZW6 to be merged (in a CR.....ast file it looks like).

How did you manage to get the key extracted? I was unable to go the backup route and used the file manager from https://bstweaker.tk/ 6.9.2 beta.

[Sirtel]

Originally Posted by patrik

It was for several books (I checked a few, all newer than Jan 3).

Here is a free book you can check if you like:

https://www.amazon.com/Know-What-You...dp/B0BX4B1VX5/

Worked for me in Bluestacks.

[patrik]

Very interesting.

Do you both use the kindle app version 4.16?

[Sirtel]

Originally Posted by patrik

Very interesting.

Do you both use the kindle app version 4.16?

I do, yes.